The virtual server products offered by the leading virtualization vendors each have strengths and weaknesses. Plus: a look inside the newest trends in the virtualization market.
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A lot has happened in the last several months of 2009 since last we last compared virtual servers. Citrix has made Xen Server free and released a new version 5.5 in mid 2009. Microsoft has released R2 of Windows Server 2008 that extends Hyper-V in new and useful ways, and adds support for Red Hat Linux guest OSs finally. And VMware has come out with about 57 new products, mostly labeled as version 4, to manage and integrate their line, and handle greater densities of VMs per server.
Before we rate the various virtualization vendors, here are some issues that are either no longer as relevant or that haven't much changed from last year's virtualization comparison:
1. No one cares anymore whether there are any pre-installed hypervisors when they buy their server hardware.
Part of the problem with the pre-installs was a confusing story from VMware, and a lack of OEM focus from Citrix for Xen.
Most OEMs want to build their own servers anyway, so they can get more money from you on services and support on post-sale anyway. Look instead in 2010 for a few vendors to start shipping specialized virtual servers, like the Cisco Unified Communications Platform that begun shipping in mid-2009. These will be able to densely pack VMs by the truckload perhaps as much as terabyte RAM densities, which are needed to support dozens or hundreds of VM instances.
Microsoft's Hyper-V Server 2008 R2 can handle new CPU features called Rapid Virtualization Indexing by AMD and Extended Page Tables by Intel that will boost performance for VMs running on those machines.
2. Pre-built virtual appliances haven't really gone anywhere for Citrix or Microsoft.
VMware is still in the best position here, although Xen at least puts up this page that shows you how to assemble a pre-built appliance.
Citrix is focused more on its Project Kensho, which enables import and exporting virtual appliances in the Open Virtual Machine Format that it shares with Microsoft. Citrix also has a series of Amazon Elastic Cloud resources called the Citrix Cloud Center that puts all of its various network and virtualization tools in the cloud for potential customers to experiment with.
VMware supports OVF with its vApp utility, so look for better interoperability if you want to switch hypervisors or manage mixed environments.
Next Page: Virtual Server Licensing
3. Virtual server licensing is still a total mess.
VMware hasn't done much towards simplifying its licensing, but on the low end is its vSphere essentials price of $995 that supports three physical servers with two CPUs apiece.
Windows continues to have a variety of Windows guest license programs to complicate an already difficult situation.
And while both Xen Server and Hyper-V are free, the tools to manage them aren't and can quickly add up. What would be nice would be a single price and single license. But we aren't there yet.
Yet even aside from these three issues, there are still a few areas where the vendors differ:
1. Enterprise-class VM management tools are improving but still have room to grow.
Both Citrix and Microsoft are making an effort at managing other hypervisors, making it easier for IT workers, especially those whose shops that are going virtual in big ways.
Citrix sells two versions of its Essentials management software, one for its own Xen servers and one for Hyper-V. There are minor differences between the two versions, such as that Hyper-V lacks support for the high availability that is found in the Xen version. But both share common core components such as storage link snapshots and provisioning, workflow and procedures integration, dynamic VM provisioning and load balancing.
Microsoft's System Center currently will manage both VMware and its own hypervisors, and in the next release will also handle Xen's as well, making it the most pluralistic tool.
Meanwhile, VMware hasn't been idle either on the management front, and came out with a series of new tools that can help handle more complex virtual infrastructures under its vSphere v4 update in mid-2009. There is better support for fault tolerance, better support for moving running VMs between servers, and virtual network switches integrated into the management package. It also allows users to beef up RAM, storage, and CPU while a VM is running.
And third parties continue to enter this market as they see opportunities. Hytrust's appliance came out last spring, and continues to be enhanced to enable better security policies around VM image management.
2. The three major vendors are moving toward more complete VDI solutions.
The big three virtualization vendors have made some major strides toward Virtual Desktop Infrastructure in the past nine months. VDI refers to the ability to store boot images of desktops on a central storage repository, and send them to a thin client or other device to run.
This doesn't obviate the need for various third-party tools such as connection brokers and storage managers, but at least they are all moving in the right direction. Microsoft has the most improved among the three with its R2/Windows 7 combination of features (as we mentioned earlier) that make VDI implementation easier.
And VMware continues to enhance its series of management tools under its View line that include thin client agents, desktop management, connection brokers and more. They have come up with a new remote protocol called PC over IP that looks promising, too.
Next Page: Virtual Server Comparison Chart
3. iPhone apps aplenty.
Well, there may be more than 170 different iPhone apps that can make rude bodily noises, so virtualization vendors have a ways to catch up there. But there are a few good iPhone apps that are worthy of IT workers' attention.
Wyse has its PocketCloud iphone app, which costs $40 and doesn't have very good documentation and has a confusing series of Web pages. And there are Windows remote desktop clients, VNC clients, and even a Webex and LogMeIn clients too, making remote control of your desktops from your iPhone easier, although scrolling around its miniscule screen can get tiring.
But let's give Citrix kudos for their Citrix Receiver for iPhone app, which is free. You can remotely control a desktop from your iPhone, as well as use it to connect to a XenApp or Presentation server host and run Windows apps. They include a demo system that you can connect to see the various features involved, which is very smart. It comes with a feature called DocFinder, which helps you locate documents on your network servers. You can also host or join Goto Meetings too.
Citrix: A, for reasons above. This is the ideal for other IT iPhone apps.
VMware, Microsoft: both get an F, no iPhone apps yet from them.
Virtual server comparison: VMware vs. Microsoft vs. Citrix/Xen